Chapter 8 - Respiration Flashcards
Vital Capacity (VC)
The maximal volume of air that can be inhaled by the lungs with each breath. This is the amount of air we actually (or vitally) use.
Total lung capacity (TLC)
The maximum volume of air that the lungs can hold, which include the vital capacity (VC) and the residual volume (RV)
Residual volume (RV)
The amount of air that must remain in the lung at all times in order to prevent lung collapse
What is the relationship between total lung capacity (TLC), residual volume (RV), and vital capacity (VC)?
Total lung capacity (TLC) is the vital capacity (VC) plus the residual volume (RV)
TLC = RV + VC
Expiratory Reserve Volume (ERV)
The amount of air that can be forcibly exhaled after a normal exhalation.
Tidal volume
The volume of air that is normally inhaled or exhaled with each breath
Inspiratory reserve volume (IRV)
The amount of air which can be taken into the lungs, beyond one’s tidal volume, using a forced inspiration.
What is the relationship between tidal volume (TV), vital capacity (VC), inspiratory reserve volume (IRV), and expiratory reserve volume (ERV)?
Vital capcity (VC), the total amount of gas that can be moved, is equal to the sum of the inspiratory reserve volume (IRV), expiratory reserve volume (ERV), and tidal volume (TV).
VC = TV + IRV + ERV
Label the regions of the lung capacity graph and understand their relations
Where does gas exchange occur in adults?
gas exchange occurs in the lungs. Specifically, it occurs in the alveoli of the lungs.
What is the passage that air takes through the respiratory tract during inhalation
external nares → nasal cavity → pharynx → larynx → trachea → bronchi → bronchioles → alveoli (site of gas exchange)
What important purposes do the mouth and nose serve during breathing?
They act as a filtration system by removing dirt and particulate matter from the air (via mucous membranes, nasal hairs, and cilia).
They warm and humidify the air before it reaches the lungs.
Each alveolus is coated in surfactant. What is it, and what function does it play in respiration?
A liquid substance produced by the lung that reduces surface tension in the alveoli. Surfactant prevents lung collapse and decreases the effort needed to expand the lungs (inhale).
What filtration mechanisms are present in the bronchi and trachea?
The bronchi and trachea contain ciliated epithelial cells to catch material that may have made it past the initial filtration mechanisms in the nasal cavity.
What function does the branching and continual subdivision of the bronchi, bronchioles, and alveoli play in gas exchange?
The branching and minute size allow for an exceptionally large surface area for gas exchange—approximately 100 m2.
Describe the interface of gas exchange in the alveoli.
A network of capillaries surrounds each alveolus to carry oxygen and carbon dioxide for gas exchange between the respiratory and circulatory systems.
What is the function of the epiglottis?
The epiglottis keeps food out of the respiratory tract by covering the opening of the larynx (glottis) during swallowing.
Thoracic cavity
The chest cavity that contins the lungs
What role do the diaphragm and intercostal muscles play during breathing
generate the relatively negative pressure differential between each intrapleural space and its associated lung
Regarding nervous system control, what is interesting about respiration?
Although breathing is controlled autonomically by smooth muscle cells, the diaphragm is composed of skeletal muscle and therefore is under somatic control. Muscular contraction and expansion of the diaphragm regulates inspiration, which is necessary for air intake.
What are the membranes within the thoracic cavity that surround the lungs called?
The pleurae (singular pleura) are the membranes that surround each lung, and are a closed sac against which the lung grows. The surface adjacent to the lung is the visceral plerua, while all other parts of the sac are parietal. The pressure differential between the intrapleural space and the lungs is critical for breathing.
Intrapleural space
The space between two membranes (visceral pleura and parietal pleura) that cover the lungs
What physical principle and associated equation is used during ventilation?
Ventilation is based on the use of pressure and pressure differentials to do useful work in a system (to move air in and out of the lungs). It is based on Boyles law:
P1V1 = P2V2
Contraction and expansion of the diaphragm increases or decreases the lung volume (V2), leading to a decrease or increase in lung pressure (P2). The associated pressure differentials result in inhalation or exhalation, respectively.
What muscles are used during inhalation to expand the thoracic cavity? How does this result in a pressure differential that leads to inhalation?
The diaphragm and external intercostal muscles are used to expand the thoracic cavity and inrease intrapleural volume (decrease intrapleural pressure). The pressure in the lungs (atmospheric) is now higher, than the pressure in the intrapleural space, which results in expansion of the lungs into the intrapleural space (and decreased lung pressure). This results in a pressure differential in the lungs that forces air from the outside world into the lungs (inhalation).
